Ozone layer and/or global warming problems have focused considerable attention on the nature of refrigerants employed in refrigeration systems of various sorts. Some such systems, particularly those that do not have sealed compressor units as are commonly found in vehicular air conditioning systems, are prone to refrigerant leakage. Older refrigerants, HFC 12, for example, are thought to cause depletion of the ozone layer while many of the replacements, HCFC 134a, for example, are believed to contribute to the so-called “greenhouse effect” and thus global warming.
As a consequence, a considerable effort is underway to develop refrigeration systems employing transcritical refrigerants such as carbon dioxide. Carbon dioxide is plentiful in the atmosphere and may be obtained therefrom by conventional techniques and employed as a refrigerant in such systems. Should the systems leak the CO2 refrigerant, because it was originally obtained from the atmosphere, there is no net increase of the refrigerant in the atmosphere, and thus no increase in environmental damage as a result of the leak.
Transcritical refrigeration systems, such as CO2 systems, operate at relatively high pressures and require, in lieu of a condenser in a conventional vapor compression refrigeration system, a gas cooler for the refrigerant.
The heat rejected by a gas cooler can be employed for various useful purposes and one such use is for heating potable water for residential, commercial, or industrial usages. The present invention is primarily directed at providing a combination water heater and gas cooler.